1. Field of the Invention
The present invention relates to an articulation device. More particularly, the present invention relates to a simplified structure of an articulation device using a reaction force generated by an inertia body. The present invention is suitable for an articulation device for effecting a very small movement, of the order of a micrometer or a nanometer, which can be suitably used as a micro-hand.
2. Description of Related Art
In a manipulating apparatus such as an industrial robot, an articulation device is provided for realizing a flexible handling of various objects to be manipulated. Industrial fields wherein control of a movement, on the order of micrometer or nanometer, of a small sized object is required are, for example, semiconductor processes such as positioning device of a water, the biochemistry or medical fields, such as cutting a cell or a cell injection or a fine medical operation, and telecommunication satellite production, for example, positioning an antenna.
A Japanese patent application No. 59-175990 discloses an articulation device, wherein a drive mechanism having a drive motor and a gear train is utilized. However, this type of the articulation device is defective in that the motor as well as the gear train are large, which makes it difficult that this type of the articulation device is used for in field of micromachines, which is becoming important.
In view of the above, various attempts have been made to obtain articulation devices of a simple construction as well as of a reduced size. For example, an articulation device is proposed, wherein a spherical rotor is provided, which has an outer peripheral surface, which is in contact with a ultrasonic driving type stator, so that a translation wave is generated, which causes the rotor to be frictionally driven, which is published by a lecture of Japanese Robot Academy, No. 1136, November 1990. However, this type of device is defective in its short service life due to a continuous frictional contact occurred between the stator and rotor, which causes the parts to be wear quickly.
Japanese Unexamined Patent Publication No. 6-17076 discloses an articulation device having a parallel link mechanism, with six degrees of freedom, having six links each using a telescopic action of a piezoelectric element, which allows, at an end of the articulation mechanism, movement with six degrees of freedom. This type of mechanism is desirable since a fine movement of a micron order can be easily obtained. However, it is defective in that an amount of the movement is very limited.
In view of this, in order to obtain an increased stroke of the articulation mechanism, Japanese Unexamined Patent Publication No. 2-180578 proposes the improved articulation device, wherein an impact force is generated by a rapid movement of inertia bodies, which causes an arm mounted to the articulation device to be moved due to an inertia of the inertia bodies. However, this device is defective in its complicated and large sized structure due to the fact that a plurality of inertial operating mechanisms are mounted on a single arm.